Fluoroiodocarbon blends as CFC and halon replacements

ABSTRACT

A new set of effective, environmentally safe, nonflammable, low-toxicity refrigerants, solvents, foam blowing agents, propellants, and firefighting agents is disclosed. The agents are clean, electrically nonconductive, and have short atmospheric lifetimes, zero ozone-depletion potential, and low global warming potentials. The agents comprise at least one fluoroiodocarbon agent satisfying the general formula C a  H b  Br c  Cl d  F e  I f  N g  O h , wherein a is between and including 1 and 8; b is between and including 0 and 2; c, d, g, and h are each between and including 0 and 1; e is between and including 1 and 18; and f is between and including 1 and 2, either neat or mixed with additives selected from the group consisting of: alcohols, esters, ethers, fluoroethers, hydrocarbons, hydrofluorocarbons, and perfluorocarbons.

GOVERNMENT RIGHTS

The U.S. Government is granted an irrevocable, non-exclusive,nontransferable, royalty-free right to use the invention with theauthority to grant said right for governmental purposes.

This application is a division of application Ser. No. 08/027,227 filedMar. 5, 1993 now U.S. Pat. No. 5,611,210.

RELATED U.S. APPLICATION DATA

A related application entitled "Clean Tropodegradable Fire ExtinguishingAgents with Low Ozone Depletion and Global Warming Potentials,"application Ser. No. 07/800,532 was filed by Nimitz et al. on Nov. 27,1991 now abandoned.

BACKGROUND OF THE INVENTION

1. Field of the Invention (Technical Field)

The invention disclosed herein generally relates to fluoroiodocarboncompositions of matter, and methods of making and using suchcompositions of matter.

2. Background Art

Chlorofluorocarbons (CFCs) such as CFC-11, CFC-12, CFC-113, CFC-114,CFC-115, and blends containing these CFCs such as R-500 and R-502 arecurrently used as refrigerants, solvents, foam blowing agents, andpropellants. CFCs contain only chlorine, fluorine, and carbon, and havethe general formula C_(x) Cl_(y) F_(z), where X=1 or 2 and Y+Z=2X+2. Arelated group of chemicals known as halons (also calledbromofluorocarbons, BFCs), having the general formula C_(w) Br_(x)Cl_(y) F_(z) (where W=1 or 2, Y=0 or 1, and X+Y+Z=2W+2) are in currentuse as firefighting agents.

Because of the great chemical stability of CFCs and halons, when theyare released to the atmosphere only minuscule fractions are destroyed bynatural processes in the troposphere. As a result, CFCs and halons havelong atmospheric lifetimes and migrate to the stratosphere where theyundergo photolysis, forming chlorine and bromine radicals that seriouslydeplete the earth's protective ozone layer. Each chemical is assigned anozone-depletion potential (ODP) that reflects its quantitative abilityto destroy stratospheric ozone. The ozone depletion potential iscalculated in each case relative to CFC-11 (CFCl₃,trichlorofluoromethane), which has been assigned a value of 1.0.Currently used CFCs have ODPs near 1; halons have ODPs between 2 and 14.Names, formulas, and ODPs of commonly used CFCs and halons are shown inTable 1.

                  TABLE 1                                                         ______________________________________                                        NAMES, FORMULAS, AND ODPs OF CFCS IN CURRENT USE                              AS REFRIGERANTS, SOLVENTS, FOAM BLOWING AGENTS, AND                           PROPELLANTS                                                                   CFC or                                                                        Halon   Name                Formula   ODP                                     ______________________________________                                        CFC-11  trichlorofluoromethane                                                                            CCl.sub.3 F                                                                             1.0                                     CFC-12  dichlorodifluoromethane                                                                           CCl.sub.2 F.sub.2                                                                       1.0                                     CFC-113 1,1,2-trichloro-1,2,2-trifluoroethane                                                             CCl.sub.2 FCClF.sub.2                                                                   1.1                                     CFC-114 1,2-dichloro-1,1,2,2-tetrafluoroethane                                                            CClF.sub.2 CClF.sub.2                                                                   0.8                                     CFC-115 chloropentafluoroethane                                                                           CClF.sub.2 CF.sub.3                                                                     0.5                                     R-500   --.sup.a            --        0.3                                     R-502   --.sup.b            --        0.7                                     Halon 1211                                                                            bromochlorodifluoromethane                                                                        CBrClF.sub.2                                                                            4.1                                     Halon 1301                                                                            bromotrifluoromethane                                                                             CBrF.sub.3                                                                              12.5                                    Halon 2402                                                                            1,2-dibromotetrafluoroethane                                                                      CBrF.sub.2 CBrF.sub.2                                                                   3.9                                     ______________________________________                                         .sup.a. azeotropic blend of CCl.sub.2 F.sub.2 (CFC12, 73.8 wt. %) and         CHF.sub.2 CF.sub.3 (HFC125, 26.2 wt. %).                                      .sup.b. azeotropic blend of CCl.sub.2 CF.sub.3 (CFC115, 51.2 wt. %) and       CHClF.sub.2 (HCFC22, 48.8 wt. %).                                        

CFC-12, for example, comprises approximately 26% by weight of worldwideCFC production, and about 150 million pounds per year are produced. Thevast majority of this CFC-12 is eventually released to the atmosphere,where it rises to the stratosphere, is struck by ultraviolet radiation,and decomposes to give chlorine radicals that catalytically destroy theprotective ozone layer of the earth. This depletion of stratosphericozone allows more ultraviolet light to reach the surface of the earth,resulting in increases in human skin cancer and cataracts plus damage tocrops, natural ecosystems, and materials, in addition to other adverseeffects. This invention will significantly decrease these adverseeffects by providing environmentally safe alternative agents to use inplace of CFCs and halons.

At present, CFCs, in addition to selected hydrochlorofluorocarbons(HCFCs) and hydrofluorocarbons (HFCs) are used as refrigerants,solvents, foam blowing agents, and propellants. CFCs have been widelyused for these applications because of their effectiveness, lowtoxicity, nonflammability, electrical nonconductivity, cleanliness onevaporation, miscibility with hydrocarbon and mineral oil lubricants,and relative nonreactivity towards copper, aluminum, and ferrous metals.However, CFCs are being phased out of production in the U.S. under theprovisions of the Montreal Protocol, the Clean Air Act Amendments of1990, and the presidential directive of 11 Feb. 1992. Although HCFCs(with ODPs ranging from 0.02 to 0.11) deplete ozone much less than CFCs,HCFCs do cause some ozone depletion and are also scheduled to be phasedout of production eventually under the Montreal Protocol.

The broad class of halocarbons consists of all molecules that containcarbon, may contain hydrogen, and contain at least one of the followinghalogen atoms: fluorine, chlorine, bromine, or iodine. Iodocarbons arehalocarbons that contain iodine; fluoroiodocarbons contain both fluorineand iodine. Haloalkanes are a subset of halocarbons comprising compoundsmade up of only carbon, halogens, and possibly hydrogen, and having nooxygen, nitrogen, or multiple bonds. In principle, haloalkanes may bederived from hydrocarbons by substitution of halogen atoms (F, Cl, Br,or I) for hydrogen atoms. Hydrocarbons themselves have been used as veryeffective refrigerants, solvents, foam blowing agents, and propellantsbut have the major disadvantage of extremely high flammability.Substitution with a high proportion of halogen atoms impartsnonflammability. CFCs and other highly halogenated halocarbons thereforepossess many of the desirable properties of hydrocarbons plus thesubstantial advantage of nonflammability.

Toxicity is a major issue in the selection of refrigerants, solvents,foam blowing agents, propellants, and firefighting agents. For example,the toxic effects of haloalkanes include stimulation or suppression ofthe central nervous system, initiation of cardiac arrythmias, andsensitization of the heart to adrenaline. Inhalation of haloalkanes cancause bronchoconstriction, reduce pulmonary compliance, depressrespiratory volume, reduce mean arterial blood pressure, and producetachycardia. Long term effects can include hepatotoxicity, mutagenesis,teratogenesis, and carcinogenicity.

Environmental effects of halocarbons including ozone-depletion potential(ODP), global warming potential (GWP), and terrestrial impacts must beconsidered. Chlorine- and bromine-containing haloalkanes are known todeplete stratospheric ozone, with bromine posing a greater problem (peratom) than chlorine. The depletion of ozone in the stratosphere resultsin increased levels of ultraviolet radiation at the surface of theearth, causing increased incidences of skin cancer, cataracts,suppression of human immune systems, crop damage, and damage to aquaticorganisms. These problems are considered so serious that the MontrealProtocol and other legislation have placed restrictions on theproduction and use of volatile halogenated alkanes.

Flame suppression occurs by two mechanisms: physical and chemical. Thephysical mechanism involves heat absorption by the molecules sufficientto lower the temperature of the combusting materials below the ignitionpoint and/or displacement of oxygen thereby terminating combustion. Thelarger the extinguishant molecule (the more atoms and bonds it contains)the more degrees of vibrational freedom it has, the higher the vaporheat capacity, and the greater the heat removal. The chemical mechanisminvolves interruption of free radical flame-propagation chain reactionsinvolving hydrogen, oxygen, and hydroxyl radicals. It has beenspeculated (but not proven) that bromine atoms disrupt these chainreactions.

Previous firefighting agents utilized either chemical or physical actionor both to achieve flame extinguishment. Agents such as carbon dioxidedisplace oxygen and also absorb thermal energy. Agents such as waterfunction solely by thermal energy absorption. Previous halogenatedagents such as carbon tetrachloride, bromotrifluoromethane, etc. employboth functional means. U.S. Army studies on halogenated agents in the1940's resulted in the adoption of the well known Halon family ofagents. Other work by New Mexico Engineering Research Institute hasidentified neat perfluorocarbons and some neat iodinated agents ashaving future potential as firefighting agents (Nimitz. et al., "CleanTropodegradable Fire Extinguishing Agents with Low Ozone Depletion andGlobal Warming Potentials," co-pending U.S. patent application Ser. No.07/800,532 filed by Nimitz et al. on Nov. 27, 1991). In this work a fewiodine-containing chemicals in neat form were shown to exhibit similarextinguishment properties to bromine-containing chemicals.

There are many concerns regarding brominated, perfluorinated, and neatiodinated agents. Brominated agents are presently being eliminated fromworldwide production, pursuant to the adoption of the Montreal Protocoland the Clean Air Act of 1990, due to their tremendous potential todestroy the stratospheric ozone layer. Perfluorinated agents have highglobal warming potential and atmospheric lifetimes estimated to beseveral thousand years. Their production and use is being restricted bypending legislation and liability concerns of current manufacturers. Thecosts of perfluorocarbons are high and their firefighting performance isless than that of the brominated agents. In weight and volume criticalsituations such as aircraft, tanks, and ships, the additional quantityrequired for extinguishment cannot be tolerated. One neat iodinatedagent (trifluoroiodomethane, CF₃ I) has long been known to havefirefighting potential (Dictionary of Organic Compounds, Chapman andHall, New York, 1982, p. 5477). Concerns about CF₃ I revolve aroundtoxicity and dispersion effectiveness. Bromotrifluoromethane (CF₃ Br)was the choice agent for such gaseous flooding applications and hasremained so until the present time.

Refrigerants, solvents, foam blowing agents, propellants, andfirefighting agents must be chemically stable during storage and useover long periods of time and must be unreactive with the containmentsystems in which they are housed. Refrigerants normally operate betweenthe temperature extremes of -98° C. to 8° C. The majority ofresidential, commercial, and institutional applications lie in the rangeof -23° C. to 8° C. In extraordinary cases (e.g., motor burnout) highertemperatures may be experienced, but in such cases the formation ofother contaminants would make replacement of the fluid necessary anyway.Although solvents, foam blowing agents, and propellants are normallystored and used at room temperature, they may under unusualcircumstances experience transient temperatures up to 150° C. duringstorage. Firefighting agents must be stable on storage at temperaturesof -20° C. to 50° C., and should decompose at flame temperatures toyield radical-trapping species.

A refrigerant operates by absorbing heat as it evaporates in one regionof the apparatus, then gives up the heat as it recondenses in anotherportion of the apparatus. The required properties for effectivenessinclude appropriate vapor pressure curves, enthalpies of vaporization,solubility behavior (including oil miscibility), toxicity, andflammability. CFCs 12, 114, 500, and 502 have been used as refrigerantsfor many years because they possess the required physical propertiessuch as appropriate boiling points and operating pressures, enthalpiesof vaporization, miscibility with mineral oil-based lubricants, lowtoxicity and nonflammability. In addition, CFCs are relativelynoncorrosive to metals and seal materials. Properties of commonly-usedrefrigerants (including typical evaporator and condenser temperaturesand typical usages) are set forth in Table 2.

                                      TABLE 2                                     __________________________________________________________________________    TYPICAL EVAPORATOR AND CONDENSER TEMPERATURES                                 FOR CFC REFRIGERANTS                                                          CFC                                                                              Evap. Temp (F.°)                                                                Cond. Temp (F.°)                                                                Typical Usages                                           __________________________________________________________________________    11 35 to 40  95 to 105                                                                             Centrifugal chillers, solvent, foam agent                12 -10 to 35                                                                              105 to 125                                                                             Auto A/C, freezers, window A/C units                     13 -50 to -75                                                                             100 to 125                                                                             Very low temp freezers                                   113                                                                              35 to 40  95 to 105                                                                             Centrifugal chillers, solvent, cleaner                   114                                                                              -24 to 35                                                                              100 to 125                                                                             Marine chillers, low temp freezers                       115                                                                              -50      100 to 125                                                                             Low temp freezers                                        500                                                                              -30 to -80                                                                             100 to 125                                                                             Supermarket cases, vending machines,                                          commercial transport                                     502                                                                               40 to -100                                                                            100 to 125                                                                             Low temp refrigeration                                   503                                                                              -100 to -200                                                                           100 to 125                                                                             Cryogenic freezers                                       __________________________________________________________________________

Hydrocarbons including cyclopropane, propane, butane, and isobutane havealso been used as highly effective refrigerants. However, hydrocarbonshave found little commercial use as refrigerants because of their highflammability. They possess all of the other required properties TheASHRAE Standard 15 limits the use of most hydrocarbons as Class 2 or 3refrigerants, limiting their use to laboratory equipment with a totalcharge of less than 3 pounds or to technical/industrial applicationswherein the refrigeration equipment is located remotely from inhabitedbuildings. These restrictions severely limit the current utility ofrefrigerants containing hydrocarbons.

Refrigeration equipment requires lubricant constantly circulating in therefrigerant fluid to avoid friction, overheating, and burnout of thecompressor or bearings. Therefore miscibility of refrigerants withlubricants is an essential requirement. For example, most lubricants arenot very soluble in hydrofluorocarbons (HFCs), and this has presentedmajor problems in the use of the alternative agent HFC-134a forrefrigeration.

Many billions of dollars worth of installed refrigeration andair-conditioning equipment currently exists. If CFCs become unavailableand no drop-in replacements are available, much of this equipment willbe rendered inoperable and may wind up in landfills. The useful lifetimewill be shortened drastically, and a significant fraction of the energyand resources put into manufacturing and installing the equipment willbe wasted.

A solvent must dissolve hydrophobic soils such as oils, greases, andwaxes, should be nonflammable and relatively nontoxic, and shouldevaporate cleanly. For solvents, chemicals with boiling points between35° C. and 120° C. are preferred, because this boiling point rangeallows evaporation in reasonable time (between one minute and twohours). Traditionally, CFC-113 and 1,1,1-trichloroethane have beensolvents of choice. Recently, because of environmental concerns abouthalogenated solvents, interest in hydrocarbon solvents such as Stoddardsolvent (a petroleum fraction of eight- to eleven-carbon hydrocarbons)has revived, despite the flammability of these solvents. When referringto hydrocarbon petroleum fractions, it is commonly understood that theterms ligroin, mineral spirits, naphtha, petroleum ether, and petroleumspirits may represent fractions with similar compositions and may attimes be used interchangeably.

A foam blowing agent must create uniform, controllable cell size in apolymer matrix, and preferably should provide high insulation value andbe nonflammable. For foam blowing a wide variety of agents has beenused, including CFC-11, HCFC-22, HCFC-123, HFC-134a, HCFC-141b, andpentane. Water is often added in the foam blowing agent (up to about 25%by moles) to react with the forming polymer, liberating carbon dioxideand aiding cell formation. More recently, some manufacturers haveshifted to using water as the exclusive blowing agent, despite slightlosses in insulating ability, dimensional stability, and resistance toaging.

An aerosol propellant must have a high vapor pressure, low heat ofvaporization, and stability on storage. In the U.S., CFCs were used aspropellants until 1978, and in many countries CFCs are still in use forthis purpose. The continued use of CFC aerosol propellants overseascontributes substantially to stratospheric ozone depletion. After 1978in the U.S. CFCs were replaced by the hydrocarbons butane and isobutanefor many propellant applications. These gases are extremely flammableand people have been burned in fires involving these propellants.

Firefighting agents to replace halons must be effective extinguishants,relatively nontoxic, electrically nonconductive, must evaporate cleanly,and must have low environmental impact. Halons (bromofluorocarbons),although they meet the first four criteria, have long atmosphericlifetimes and high ozone-depletion potentials, and will be phased out ofproduction under the terms of the Montreal Protocol and otherregulations.

Although it is relatively easy to identify chemicals having one, two, orthree selected properties, it is very difficult to identify chemicalsthat possess simul-taneously all of the following properties: effectiveperformance, nonflammability, low toxicity, cleanliness, electricalnonconductivity, miscibility with common lubricants, short atmosphericand environmental lifetimes, zero ODP, and very low GWP. Furthermore,the unusual and desirable properties of selected members of the obscureclass of fluoroiodocarbons are by no means obvious. Fluoroiodocarbonshave only rarely been studied, and very few of their properties arereported in the literature. Conventional chemical wisdom indicates thatiodine-containing organic compounds are too toxic and unstable to usefor these purposes, and iodocarbons have been rejected on those groundsby the majority of those skilled in the art. Partly as a result of thisprejudice, the properties of the class of fluoroiodocarbons have beeninvesti-gated only slightly, and fluoroiodocarbons have remained alittle-known class of chemicals.

An important part of this invention is recognizing that the uniqueproperties of fluorine (the most electronegative element) strengthen andstabilize a carbon-to-iodine bond sufficiently to render selectedfluoroiodocarbons relatively nontoxic and stable enough for use insolvent cleaning, refrigeration, foam blowing, and aerosol propulsion.Painstaking collection and estimation of properties and screening forexpected effectiveness, low toxicity, and low environmental impact havebeen carried out to identify them as being suitable for these new uses.Disclosed herein therefore are both new uses and new combinations ofchemicals, leading to new and unexpected results.

Both the neat and blended fluoroiodocarbons described herein providenew, environmentally safe, nonflammable refrigerants, solvents, foamblowing agents, aerosol propellants, and firefighting agents. Thesecompounds have the characteristics of excellent performance,cleanliness, electrical nonconductivity, low toxicity, nonflammability(self-extinguishment), short atmospheric lifetime, zero ODP, low GWP,and negligible terrestrial environmental impact.

Although some fluoroiodocarbons are described briefly in the knownchemical literature, their potential for the uses described herein hasnever been previously recognized. No fluoroiodocarbons have been usedbefore for solvent cleaning, refrigeration, foam blowing, or aerosolpropulsion, either in neat form or in blends. One neat fluoroiodocarbon(CF₃ I) has been briefly described as a firefighting agent in the openliterature (Dictionary of Organic Compounds, Chapman and Hall, New York,1982, p. 5477). A small number of additional neat fluoroiodocarbons hasbeen proposed by one of the current inventors for use in firefighting(Nimitz et al., "Clean Tropodegradable Fire Extinguishing Agents withLow Ozone Depletion and Global Warming Potentials," co-pending U.S.patent application Ser. No. 07/800,532, filed Nov. 27, 1991). However,neither any blends containing fluoroiodocarbons nor the new neatfluoroiodocarbon agents described herein have ever before been proposedfor use in firefighting or any of the other uses described herein. Theseblends and new neat agents offer substantial advantages in terms oflower cost, lower toxicity, improved physical properties, and greatereffectiveness.

SUMMARY OF THE INVENTION (DISCLOSURE OF THE INVENTION)

A primary object of the invention is the provision of relativelynontoxic agents for use in refrigeration, solvent cleaning, foamblowing, aerosol propulsion, and firefighting. Another object of theinvention is the provision of nonflammable and environmentally safecompositions of matter. Yet another object of the invention is theprovision of fluoroiodocarbon compounds that are clean and electricallynonconductive. Still another object of the invention is the provision ofneat and blended fluoroiodocarbons having zero ozone-depletionpotential, low global warming potential, and negligible atmospheric andterrestrial environmental impacts.

An advantage of the invention is the duplication of existingrefrigerants, solvents, foam blowing agents, aerosol propellants, andfirefighting agents at lower cost. Another advantage of the invention isoptimization of properties by blending of fluoroiodocarbons withselected additives. Still another advantage of the invention is theprovision of effective and, in some cases, superior compositions offluoroiodocarbons as replacements for existing chemical compounds.

DESCRIPTION OF THE PREFERRED EMBODIMENTS (BEST MODES FOR CARRYING OUTTHE INVENTION)

Desirable agents must possess all of the following properties:effectiveness, low toxicity, nonflammability, and environmental safety.Although it is relatively to easy find chemicals that meet two or threeof these criteria, it is extremely difficult to identify chemicals thatmeet all desired criteria. The novelty of this invention lies inidentifying chemical compounds and blends (and methods of using these)that meet all these criteria. The chemical compounds and blendsdescribed herein are effective, relatively nontoxic, nonflammable, andenvironmentally benign. They have the desired boiling points, vaporpressures, and heats of vaporization for optimal effectiveness. Bymixing a fluoroiodocarbon with another chemical several major advantagesare obtained. First, and perhaps most importantly, the mixture isrendered completely nonflammable. Second, by appropriate blending ofchemicals, the physical properties (including boiling range, density,viscosity, and lubricant solubility) can be optimized to obtain maximumperformance. Third, the already low toxicity can be further reduced.Fourth, the cost of the agent is reduced.

As a general class, iodocarbons are more reactive, less stable, and moretoxic than the corresponding chloro- or bromocarbons; for this reasonthey have often been rejected as unsuitable for the applicationsdescribed here. However, an important part of this invention isrecognizing the fact that the unique properties of fluorine givepolyfluorinated iodocarbons exceptionally low reactivity, highstability, and low toxicity. Because fluorine is the mostelectronegative element, the presence of two or more fluorine atomsattached to the same carbon atom which is bonded to the iodine atomwithdraws electron density and provides steric hindrance, making thecarbon-to-iodine bonds in fluoroiodocarbons abnormally strong andresistant to chemical reaction. All of the three common mechanisms ofchemical reaction are inhibited in fluoroiodocarbons: unimolecularnucleophilic substitution (S_(N) 1), bimolecular nucleophilicsubstitution (S_(N) 2), and homolytic bond cleavage. Because of this lowreactivity, fluoroiodocarbons exhibit unusually high stability and lowtoxicity. In addition, iodocarbons have never been implicated in ozonedepletion, global warming, or long-term terrestrial environmentalcontamination.

In applying the selection criteria of the invention, with regard totoxicity, each of the preferred compounds is characterized by acutetoxicity (either measured or predicted) no greater than that ofcurrently used CFCs. In this regard, toxicity is measured as LC₅₀(lethal concentration at the fifty percent level) for rats over anexposure period of 4 hours. Toxicity data on fluoroiodocarbons islimited at this time but highly encouraging. All of the followingfluoroiodocarbons are reported to have mice 1-hour LC₅₀ s of greaterthan 10,000 ppm: 1-iodoperfluoroethane, 1-iodo-perfluorobutane, and1-iodoperfluorohexane.

If a chemical is to have zero ODP it must either (1) not containchlorine nor bromine, or (2) undergo rapid and complete destruction bynatural processes in the troposphere (and thus never reach thestratosphere). The three major mechanisms for destruction of halocarbonsin the troposphere are photolysis, attack by hydroxyl radical (OH), andattack by oxygen atoms (O). In the troposphere, because of shielding bystratospheric ozone and other atmospheric components, the sunlightpresent is of longer wavelength (and correspondingly lower energy) thanthe light present in the stratosphere. If molecules are to be photolyzedin the troposphere they must contain light-absorbing groups(chromophores) and weak bonds. Such light-absorbing groups with weakbonds include carbon-to-iodine sigma bonds. Carbon-to-iodine bonds areextremely sensitive to photolysis and cleave easily in the presence ofsunlight, even at ground level. Thus, fluoroiodocarbons are destroyedrapidly by photolysis in the troposphere and thus do not contribute toozone depletion or substantially to global warming.

The compounds of the present invention are also selected on the basis oftheir global warming potentials, which are increasingly being consideredalong with ozone depletion factors. Global warming is caused byabsorption by molecules in the atmosphere of infrared radiation leavingthe surface of the earth. The longer the atmospheric lifetime and thegreater the infrared absorption of a molecule, the greater its GWP. Itis recognized that some chlorofluorocarbons have GWPs several thousandtimes that of carbon dioxide. Because of their rapid photolysis andresulting short atmospheric lifetimes, fluoroiodocarbons have greatlyreduced GWPs compared to CFCs, halons, HCFCs, HFCs, andperfluorocarbons.

The short atmospheric lifetimes of fluoroiodocarbons are due to thepreferential absorption of ultraviolet energy by the carbon-to-iodinebond, causing the agent to decompose in natural sunlight within a shortperiod after it enters the atmosphere. Decomposition byproducts areharmless salts which are cleansed from the environment by naturalprecipitation. A fluoroiodocarbon may even contain a chlorine or bromineatom without causing measurable stratospheric ozone depletion becausethe molecule will be destroyed by photolysis of the C--I bond in thetroposphere, never reaching the stratosphere.

In addition to undergoing rapid photolysis, iodoalkanes undergo fasterhydrolysis than the corresponding chloro- or bromoalkanes; thus theydegrade rapidly in natural waterways to form harmless products such aspotassium iodide (a common additive to table salt). Because of thisrapid degradation, fluoroiodocarbons (in contrast to CFCs) have neverbeen implicated in long-term soil or ground water contamination.

Fluoroiodocarbons are highly effective flame suppression agents, in somecases more effective on a per-mole basis than halons(bromofluorocarbons). Fluoroiodocarbons not only provide chemicalextinguishment, but significant physical extinguishment through heatremoval by molecular vibrations. Addition of a sufficient concentrationof a fluoroiodocarbon to an otherwise flammable liquid or vapor (such asa hydrocarbon) renders the material self-extinguishing. The inventiondescribed and claimed herein is specifically related to liquid andgaseous chemical agents used to extinguish active and near active firesinvolving combustible, flammable, and electrically energized materials.

The agents described herein have acceptable stability on storage undernormal conditions. To prevent photolysis of the fluoroiodocarbons, theyshould be protected from sunlight by storage in opaque containers suchas metal cylinders or brown glass bottles. If desired, for long-termstorage a small amount of copper metal can be added to enhance thestability of the iodides.

The preferred fluoroiodocarbons meeting the selection criteria are setforth in Table 3 below. All the fluoroiodocarbon agents have boilingpoints between -25° C. and +170° C. and satisfy the general chemicalformula C_(a) H_(b) Br_(c) Cl_(d) F_(e) I_(f) N_(g) O_(h), wherein a isbetween and including 1 and 8; b is between and including 0 and 2; c, d,g, and h are each between and including 0 and 1; e is between andincluding 1 and 17; and f is between and including 1 and 2.

                                      TABLE 3                                     __________________________________________________________________________    PREFERRED FLUOROIODOCARBON AGENTS.                                            Name(s)                              Formula                                  __________________________________________________________________________    bromodifluoroiodomethane             CBrF.sub.2 I                             chlorodifluoroiodomethane            CClF.sub.2 I                             1,1,2,2,3,3,4,4,5,5-decafluoro-1,5-diiodopentane, 1,5-diiodoperfluoropenta    ne                                   I(CF.sub.2).sub.5 I                      difluorodiiodomethane                CF.sub.2 I.sub.2                         difluoroiodomethane                  CHF.sub.2 I                              1,1,2,2,3,3,4,4,5,5,6,6-dodecafluoro-1,6-diiodohexane, 1,6-diiodoperfluoro    hexane                               I(CF.sub.2).sub.6 I                      fluoroiodomethane                    CH.sub.2 FI                              1,1,1,2,3,3,3-heptafluoro-2-iodopropane, perfluoroisopropyl                                                        CF.sub.3 CFICF.sub.3                     1,1,2,2,3,3,3-heptafluoro-1-iodopropane, perfluoropropyl                                                           CF.sub.3 CF.sub.2 CF.sub.2 I             1,1,2,2,3,3-hexafluoro-1,3-diiodopropane, 1,3-diiodoperfluorpropane                                                I(CF.sub.2).sub.3 I                      1-iodoheptadecafluorooctane, 1-iodoperfluorooctane, perfluorooctyl                                                 CF.sub.3 (CF.sub.2).sub.7 I              iodoheptafluorocyclobutane, iodoperfluorocyclobutane                                                               cyclo-(CF.sub.2).sub.3 CFI               1-iodopentadecafluoroheptane, 1-iodoperfluoroheptane, perfluoroheptyl         iodide                               CF.sub.3 (CF.sub.2).sub.6 I              iodbpentafluorobenzene               C.sub.6 F.sub.5 I                        iodopentafluorocyclopropane, iodoperfluorocyclopropane,                       perfluorocyclopropyl iodide          CF.sub.2 CF.sub.2 CFI                    1-iodotridecafluorohexane, 1-iodoperfluorohexane, perfluorohexyl                                                   CF.sub.3 (CF.sub.2).sub.5 I              1-iodoundecafluoropentane, 1-iodoperfluoropentane, perfluoropentyl                                                 CF.sub.3 (CF.sub.2).sub.4 I              N-iodobis-(trifluoromethyl)amine     (CF.sub.3).sub.2 NI                      1,1,2,2,3,3,4,4,4-nonafluoro-1-iodobutane, 1-iodoperfluorobutane,             perfluorobutyl iodide                CF.sub.3 (CF.sub.2).sub.3 I              1,1,2,2,3,3,4,4-octafluoro-1,4-diiodobutane, 1,4-diiodoperfluorobutane                                             I(CF.sub.2).sub.4 I                      pentafluoroiodoethane, perfluoroethyl iodide                                                                       CF.sub.3 CF.sub.2 I                      1,1,2,2-tetrafluoro-1,2-diiodoethane, 1,2-diiodoperfluoroethane                                                    CF.sub.2 ICF.sub.2 I                     1,1,2,2-tetrafluoro-1-iodoethane     CF.sub.2 ICHF.sub.2                      1,1,2-trifluoro-1-iodoethane         CF.sub.2 ICH.sub.2 F                     trifluoroiodomethane, trifluoromethyl iodide                                                                       CF.sub.3 I                               trifluoromethyl-1,1,2,2-tetrafluoro-2-iodoethyl ether                                                              CF.sub.3 OCF.sub.2 CF.sub.2 I            __________________________________________________________________________

Preferred additives for blending with fluoroiodocarbons are shown inTable 4. Table 4 includes selected alcohols, esters, ethers,hydrocarbons, hydrofluorocarbons, fluoroethers, ketones, andperfluorocarbons with boiling points between -150° C. and +200° C.

Azeotropic blends are particularly preferred because they do not changecomposition on evaporation and thus do not change properties if part ofthe mixture evaporates. We have developed a proprietary computer programfor predicting azeotrope formation based on the Soave-Redlich-Kwongequation of state and have screened the fluoroiodocarbon blendsdescribed herein to identify likely azeotropes. This program alsoincorporates novel methods we have developed for estimating propertiesof chemicals and blends: it provides accurate estimates of vaporpressure curves, enthalpies of vaporization, and other properties ofinterest, allowing selection of optimal blends.

                                      TABLE 4                                     __________________________________________________________________________    PREFERRED ADDITIVES TO BE BLENDED WITH FLUOROIODOCARBONS                      Class    Name(s)              Formula                                         __________________________________________________________________________    alcohol  1-butanol            HO(CH.sub.2).sub.3 CH.sub.3                              2-butanol            CH.sub.3 CH(OH)CH.sub.2 CH.sub.3                         ethanol              CH.sub.3 CH.sub.2 OH                                     methanol             CH.sub.3 OH                                              2-methyl-1-propanol  HOCH.sub.2 CH(CH.sub.3)CH.sub.3                          2-methyl-2-propanol  (CH.sub.3).sub.3 COH                                     1-pentanol           CH.sub.3 (CH.sub.2).sub.4 OH                             2-pentanol           CH.sub.3 CHOHCH.sub.2 CH.sub.2 CH.sub.3                  1-propanol           HO(CH.sub.2).sub.2 CH.sub.3                              2-propanol           (CH.sub.3).sub.2 CHOH                           ester    ethyl acetate        CH.sub.3 COOCH.sub.2 CH.sub.3                            ethyl butanoate, ethyl butyrate                                                                    CH.sub.3 (CH.sub.2).sub.2 COOCH.sub.2                                         CH.sub.3                                                 ethyl propanoate, ethyl propionate                                                                 CH.sub.3 CH.sub.2 COOCH.sub.2 CH.sub.3                   isobutyl acetate     (CH.sub.3).sub.2 CHCH.sub.2 OCOCH.sub.3                  isopropyl acetate    CH.sub.3 COOCH(CH.sub.3).sub.2                           methyl acetate       CH.sub.3 COOCH.sub.3                                     methyl butanoate, methyl butyrate                                                                  CH.sub.3 (CH.sub.2).sub.3 COOCH.sub.3                    methyl propanoate, methyl propionate                                                               CH.sub.3 (CH.sub.2).sub.2 COOCH.sub.3                    n-butyl acetate      CH.sub.3 (CH.sub.2).sub.3 OCOCH.sub.3                    hexyl acetate        CH.sub.3 (CH.sub.2).sub.5 OCOCH.sub.3                    n-pentyl acetate, amyl acetate                                                                     CH.sub.3 (CH.sub.2).sub.4 OCOCH.sub.3                    n-propyl acetate     CH.sub.3 (CH.sub.2).sub.2 OCOCH.sub.3                    sec-butyl acetate    CH.sub.3 CH.sub.2 CH(CH.sub.3)OCOCH.sub.3       ether    diethyl ether, ethyl ether                                                                         (CH.sub.3 CH.sub.2).sub.2 O                              diisopropyl ether, isopropyl ether                                                                 ((CH.sub.3).sub.2 CH).sub.2 O                            dimethyl ether, methyl ether                                                                       CH.sub.3 OCH.sub.3                                       di-n-butyl ether, butyl ether                                                                      (CH.sub.3 (CH.sub.2).sub.3).sub.2 O                      di-n-propyl ether, propyl ether                                                                    (CH.sub.3 CH.sub.2 CH.sub.2).sub.2 O                     1,4-dioxane          cyclo-(CH.sub.2 CH.sub.2 O).sub.2                        ethylene oxide, 1,2-epoxyethane                                                                    CH.sub.2 OCH.sub.2                                       propylene oxide, 1,2-epoxypropane                                                                  CH.sub.2 OCHCH.sub.3                                     tetrahydrofuran      cyclo-(CH.sub.2).sub.4 O                        fluoroether                                                                            bis-difluoromethyl ether                                                                           (CHF.sub.2).sub.2 O                                      hexafluorodimethyl ether, perfluorodimethyl ether                                                  (CF.sub.3).sub.2 O                                       hexafluorooxetane, perfluorooxetane                                                                cyclo-(CF.sub.2).sub.3 O                                 methyl trifluoromethyl ether                                                                       CH.sub.3 OCF.sub.3                                       octafluorodimethoxymethane                                                                         CF.sub.3 OCF.sub.2 OCF.sub.3                             octafluoro-1,3-dioxolane, perfluoro-1,3-dioxolane                                                  CF.sub.2 (OCF.sub.2 CF.sub.2).sub.2                      pentafluorodimethyl ether                                                                          CHF.sub.2 OCF.sub.3                                      1,1,2',2',2'-pentafluoro methyl ethyl ether                                                        CHF.sub.2 OCH.sub.2 CF.sub.3                             1-trifluoromethoxy-1,1,2,2-tetrafluoroethane                                                       CF.sub.3 OCF.sub.2 CHF.sub.2                    hydrocarbon                                                                            butane               CH.sub.3 (CH.sub.2).sub.2 CH.sub.3                       cyclopropane         (CH.sub.2).sub.3                                         decane               CH.sub.3 (CH.sub.2).sub.8 CH.sub.3                       2,3-dimethylpentane  (CH.sub.3).sub.2 CHCH(CH.sub.3)CH.sub.2                                       CH.sub.3                                                 2,4-dimethylpentane  ((CH.sub.3).sub.2 CH).sub.2 CH.sub.2                     2,2-dimethylpropane  (CH.sub.3).sub.4 C                                       heptane              CH.sub.3 (CH.sub.2).sub.5 CH.sub.3                       hexane               CH.sub.3 (CH.sub.2).sub.4 CH.sub.3                       isobutane            CH.sub.3 CH(CH.sub.3).sub.2                              ligroin              blend of hydrocarbons                                    limonene             C.sub.10 H.sub.16                                        2-methylbutane       (CH.sub.3).sub.2 CH.sub.2 CH.sub.2 CH.sub.3              3-methylhexane       CH.sub.3 CH.sub.2 CH(CH.sub.3)CH.sub.2                                        CH.sub.2 CH.sub.3                                        3-methylpentane      CH.sub.3 CH.sub.2 CH(CH.sub.3)CH.sub.2                                        CH.sub.3                                                 naphtha              blend of hydrocarbons                                    nonane               CH.sub.3 (CH.sub.2).sub.7 CH.sub.3                       octane               CH.sub.3 (CH.sub.2).sub.6 CH.sub.3                       pentane              CH.sub.3 (CH.sub.2).sub.3 CH.sub.3                       petroleum ether      blend of hydrocarbons                                    petroleum spirit     blend of hydrocarbons                                    pinene               C.sub.10 H.sub.16                                        propane              CH.sub.3 CH.sub.2 CH.sub.3                               Stoddard's solvent   blend of C8 to C11 hydrocarbons                          toluene              C.sub.6 H.sub.5 CH.sub.3                                 turpentine           blend of hydrocarbons                                    undecane             CH.sub.3 (CH.sub.2).sub.9 CH.sub.3              hydrofluorocarbon                                                                      difluoromethane      CH.sub.2 F.sub.2                                         1,1-difluoroethane   CHF.sub.2 CH.sub.3                                       1,1,1,2,3,3,3-heptafluoropropane                                                                   CF.sub.3 CHFCF.sub.3                                     pentafluoroethane    CF.sub.3 CHF.sub.2                                       1,1,2,2,3-pentafluoropropane                                                                       CHF.sub.2 CF.sub.2 CH.sub.2 F                            1,1,1,2-tetrafluoroethane                                                                          CF.sub.3 CH.sub.2 F                                      1,1,1-trifluoroethane                                                                              CH.sub.3 CF.sub.3                                        trifluoromethane     CHF.sub.3                                       ketone   acetone, propanone, 2-propanone                                                                    CH.sub.3 COCH.sub.3                                      2-butanone, butanone, methyl ethyl ketone                                                          CH.sub.3 COCH.sub.2 CH.sub.3                             carbon dioxide       CO.sub.2                                                 2-hexanone, methyl butyl ketone                                                                    CH.sub.3 COCH.sub.2 CH.sub.2 CH.sub.2                                         CH.sub.3                                                 3-methyl-2-butanone  CH.sub.3 COCH(CH.sub.3).sub.2                            2-pentanone, methyl propyl ketone                                                                  CH.sub.3 COCH.sub.2 CH.sub.2 CH.sub.3           perfluorocarbon                                                                        decafluorobutane, perfluorobutane                                                                  CF.sub.3 (CF.sub.2).sub.2 CF.sub.3                       dodecafluoropentane, perfluoropentane                                                              CF.sub.3 (CF.sub.2).sub.3 CF.sub.3                       hexafluorocyclopropane, perfluorocyclopropane                                                      cyclo-(CF.sub.2).sub.3                                   hexafluoroethane, perfluoroethane                                                                  CF.sub.3 CF.sub.3                                        octafluorocyclobutane, perfluorocyclobutane                                                        cyclo-(CF.sub.2).sub.4                                   octafluoropropane, perfluoropropane                                                                CF.sub.3 CF.sub.2 CF.sub.3                               tetradecafluorohexane, perfluorohexane                                                             CF.sub.3 (CF.sub.2).sub.4 CF.sub.3                       tetrafluoromethane, perfluoromethane                                                               CF.sub.4                                        __________________________________________________________________________

Refrigerants

This invention discloses that by addition of an appropriatefluoroiodocarbon a hydrocarbon is made a more effective heat-transferfluid and is rendered self-extinguishing. Such mixtures are uniquenon-flammable hydrocarbon blends.

All the new refrigeration agents described herein including blends aremiscible with the four major groups of lubricants: mineral oil,alkylbenzenes, polyol esters (POEs), and polyalkylene glycols (PAGs).The presence of higher-atomic-weight halogen atoms (chlorine, bromine,or iodine) in an agent, because of the polarizability of these atoms,allows miscibility with these lubricants. A further advantage ofhydrocarbon-containing refrigerants is that leak detection is greatlysimplified compared to CFCs or HFCs.

As shown in Table 5, by appropriate choices of pure agents or blends,drop-in replacements can be formulated to replace CFCs in existingequipment. The agents described herein allow the replacement ofthousands of tons of CFCs in existing equipment with environmentallysafe, nonflammable, energy-efficient refrigerants. In new systemsredesigned to optimize performance for fluoroiodocarbon-containingagents, superior performance will be obtained.

Solvents

Fluoroiodocarbon agents with boiling points in the desirable range foruse as solvents include, for example,1,1,2,3,3,3-heptafluoro-1-iodopropane,1,1,1,2,3,3,3-heptafluoro-2-iodopropane, fluoroiodomethane,1,1,2,2-tetrafluoro-1-iodoethane,1,1,2,2,3,3,4,4,4-nonafluoro-1-iodobutane, difluorodiiodomethane,undecafluoro-1-iodopentane, and tridecafluoro-1-iodohexane. By additionof a fluoroiodocarbon to a flammable solvent such as a hydrocarbon,alcohol, ester, or ketone the solvent is rendered nonflammable. In thecase of blends, to prevent loss of the fluoroiodocarbon agent from theblend through evaporation, ideally the fluoroiodocarbon component shouldeither form an azeotrope or have a boiling point equal to or slightlyhigher than the other component(s).

Foam Blowing Agents

By addition of an appropriate quantity of a fluoroiodocarbon to the foamblowing agent, the foam produced is rendered nonflammable and itsinsulating abilities are improved.

Aerosol Propellants

By addition of a sufficient quantity of a volatile fluoroiodocarbon apropellant such as propane, butane, or isobutane is renderednonflammable.

Firefighting Agents

By blending selected fluoroiodocarbons with hydrofluorocarbons,perfluorocarbons, and fluoroethers, agents are obtained that are highlyeffective, non-ozone-depleting, and have low toxicity and low cost. Insome cases these blended agents provide synergism (better extinguishmentthan predicted linearly) because of the chemical extinguishment of thefluoroiodocarbon and the physical extinguishment of the additive. Thevapor pressure, effectiveness, reactivity with storage vessels anddelivery systems, weight, cost, and toxicity may all be optimized bycreating blends. Blended azeotropic and near-azeotropic fluoroiodocarbonfirefighting agents allow reduction in the cost of the delivered agentby taking advantage of their superior extinguishment capabilities andthe lower costs of hydrofluorocarbons, perfluorocarbons, andfluoroethers components compared to fluoroiodocarbons. In addition, theyform constant- and near-constant composition agents, simplifyinghandling and making performance more predicable than that ofnonazeotropic blends. Such blends retain their composition at all times,do not fractionate into separate components, remain stable, and providesuperior performance. Selected blends act as functional alternatives inexisting equipment and delivery systems, minimizing the equipmentchanges required.

Industrial Applicability

This invention is further illustrated by the following non-limitingexamples.

                                      TABLE 5                                     __________________________________________________________________________    EXAMPLES OF PREFERRED DROP-IN REPLACMENT                                      REFRIGERATION AGENTS                                                                     Examples of replacements                                           Refrigerant                                                                         BP (°C.)                                                                    Chemical(s)  Approx. Proportions (by moles)                        __________________________________________________________________________    11    23.8 C.sub.2 F.sub.5 I/n-C.sub.3 F.sub.7 I                                                      50:50                                                            n-C.sub.3 F.sub.7 I/butane/pentane                                                         5:40:55                                                          C.sub.2 F.sub.5 I/pentane                                                                  50:50                                                            C.sub.2 F.sub.5 I/diethyl ether                                                            50:50                                                            n-C.sub.3 F.sub.7 I/butane                                                                 60:40                                                 12    -29.8                                                                              CF.sub.3 I   neat                                                             CF.sub.3 I/propane                                                                         60:40                                                            CF.sub.3 I/CF.sub.3 CF.sub.2 CF.sub.3                                                      50:50                                                            CF.sub.3 I/CF.sub.3 CF.sub.2 CF.sub.3                                                      10:90  (binary azeotrope)                                        CF.sub.3 I/CHF.sub.2 CH.sub.3                                                              8:92   (binary azeotrope)                                        CF.sub.3 I/cyclobutane                                                                     10:90  (binary azeotrope)                                        CF.sub.3 I/CF.sub.3 CF.sub.2 CF.sub.3 /CHF.sub.2 CH.sub.3                                  32:22:46                                                                             (ternary azeotrope)                                       CF.sub.3 I/fluoroethane                                                                    55:45                                                            CF.sub.3 I/cyclopropane                                                                    30:70                                                 22    40.8 CF.sub.3 I/propane                                                                         5:95 or 10:90                                                    CF.sub.3 I/(CF.sub.3).sub.2 O                                                              50:50                                                            CF.sub.3 I/CHF.sub.2 OCF.sub.3                                                             5:95                                                             CF.sub.3 I/difluoromethane                                                                 40:60                                                            CF.sub.3 I/pentafluoroethane                                                               30:70                                                            CF.sub.3 I/1,1,1-trifluoroethane                                                           30:70                                                            CF.sub.3 I/perfluoropropane                                                                30:70                                                 500   -33.5                                                                              CF.sub.3 I/propane                                                                         45:55                                                            CF.sub.3 I/(CF.sub.3).sub.2 O                                                              75:25                                                            CF.sub.3 I/pentafluoroethane                                                               60:40                                                            CF.sub.3 I/perfluoroethane                                                                 60:40                                                            CF.sub.3 I/1,1,1-trifluoroethane                                                           60:40                                                            CF.sub.3 I/difluoromethane                                                                 70:30                                                            CF.sub.3 I/fluoroethane                                                                    30:70                                                            CF.sub.3 I/perfluoropropane                                                                20:80                                                 502   -45.4                                                                              CF.sub.3 I/difluoromethane                                                                 20:80                                                            CF.sub.3 I/(CF.sub.3).sub.2 O                                                              40:60                                                            CF.sub.3 I/trifluoromethane                                                                60:40                                                            CF.sub.3 I/pentafluoroethane                                                               10:90                                                            CF.sub.3 I/1,1,1-trifluoroethane                                                           10:90                                                            CF.sub.3 I/perfluoroethane                                                                 10:90                                                 __________________________________________________________________________

Solvents

The following preferred pure agents and blends meet the requirements ofsolvent performance, nonflammability, low toxicity, and lowenvironmental impact: neat 1,1,2,2,3,3,4,4,4-nonafluoro-1-iodobutane;neat undecafluoro-1-iodopentane; neat tridecafluoro-1-iodohexane; 2 to15% (by moles) 1,1,2,2-tetrafluoro-1-iodoethane with 98 to 85% hexane; 2to 15% (by moles) 1,1,2,3,3,3-heptafluoro-1-iodopropane with 98 to 85%pentane; 2 to 15% (by moles) 1,1,2,2,3,3,4,4,4-nonafluoro-1-iodobutanewith 98 to 85% hexane; 2 to 15% (by moles) tridecafluoro-1-iodohexaneplus 98 to 85% octane, nonane, and/or decane; 2 to 15% (by moles)1,1,2,2,3,3,4,4,4-nonafluoro-1-iodobutane with 98 to 85% of one or morechemicals selected from the group: methanol, ethanol, 2-butanone,2-propanol, acetone, methyl acetate, ethyl acetate, tetrahydrofuran, andhexane; and 2 to 15% (by moles) undecafluoro-1-iodopentane with 98 to85% of at least one chemicals selected from the group: heptane, ethanol,2-propanol, and 2-butanone.

Foam Blowing Agents

The following preferred pure agents and blends meet the requirements forfoam blowing agents: neat difluoroiodomethane; neatpentafluoroiodoethane; neat 1,1,2,3,3,3-heptafluoro-1-iodopropane; 2 to15% (by moles) pentafluoroiodoethane with 98 to 85% butane; 2 to 15% (bymoles) difluoroiodomethane with 98 to 85% butane; 2 to 15% (by moles)1,1,2,3,3,3-heptafluoro-1-iodopropane with 98 to 85% pentane; 2 to 15%(by moles) pentafluoroiodoethane with 98 to 85% pentane; 2 to 15% (bymoles) trifluoroiodomethane with 98 to 85% 1,1-difluoroethane; 2 to 15%(by moles) trifluoroiodomethane with 98 to 85% butane; and any of theagents in this list plus up to 40% by weight water.

Aerosol Propellants

The following nonflammable preferred blends meet the requirements foraerosol propellants: 2 to 15% (by moles) trifluoroiodomethane with 98 to85% of one or more of the chemicals selected from the group: propane,butane, isobutane, carbon dioxide.

Firefighting Agents

The following preferred blends and neat fluoroiodocarbon agents meet therequirements for effective, clean firefighting agents: blends of CF₃ Iwith at least one chemical selected from the group: trifluoromethane,difluoromethane, pentafluoroethane, and 1,1,1,2-tetrafluoroethane;blends of CF₃ CF₂ CF₂ I with at least one chemical selected from thegroup CF₃ CF₂ I, CH₂ FI, perfluoropentane, and perfluorohexane; blendsof CF₃ CF₂ CF₂ CF₂ I with perfluorohexane; and neatchlorofluoroiodomethane.

The following examples show the effectiveness of the agents listed asenvironmentally safe, nonflammable refrigerants, solvents, foam blowingagents, propellants, and firefighting agents.

EXAMPLE 1

From a household refrigerator the charge of CFC-12 (about 6 to 8 oz) isremoved and collected for recycling, reclamation, or destruction in anenvironmentally sound manner. The refrigerator is then charged from apressurized bottle through a closed system with an equivalent mass of anazeotropic blend composed of 10% (by moles) CF₃ I and 90% cyclobutane.By this process the stratospheric ozone layer has been protected andcompliance with international and national environmental regulations hasbeen achieved without harming the performance of the refrigerator,requiring new equipment, or subjecting the service technician orhomeowners to flammability or toxicity risks. As additional benefits, ifthe charge should ever escape accidentally there is no danger from it offlammability, toxicity, or ozone depletion. The stability, lowreactivity, and high materials compatibility of the agents allow them tobe stored and used for many years. The presence of CF₃ I makes itpossible to use existing mineral oil lubricants. No adverse reaction ofthe new chemicals occurs with residual CFC-12 left in the system.

EXAMPLE 2

A large commercial refrigerator is drained of CFC-12, which is collectedand recycled, reclaimed, or destroyed in an environmentally soundmanner. The refrigerator is charged with a blend of 10% (by moles)trifluoroiodomethane, 20% perfluorodimethyl ether, and 70% butane. Theperformance is nearly identical to that with CFC-12, the same mineraloil lubricant can be used, and no materials (e.g., gaskets, O-rings,tubing) must be replaced because of material incompatibilities.

EXAMPLE 3

A 200-ton centrifugal chiller is drained of CFC-11 (about 700 pounds)and filled with an equivalent mass of a blend of n-C₃ F₇I/butane/pentane (5:40:55 by moles). The chiller is re-energized andresumes normal operation without a loss in capacity or increase inenergy consumption and without retrofitting motors or seals.

EXAMPLE 4

A vapor degreaser containing CFC-113 or 1,1,1-trichloroethane is drainedand the chemical is taken for recycling, reclamation, or destruction.The vapor degreaser is filled with1,1,2,2,3,3,4,4,4-nonafluoro-1-iodobutane kept at reflux. A printedcircuit board having both through-hole and surface-mount components,contaminated during manufacturing with solder flux residue plus otheroils and waxes is passed through this vapor degreaser. The board isthoroughly cleaned, no stratospheric ozone is destroyed, and there is noflammability or toxicity risk.

EXAMPLE 5

Similar to example 4, except that the replacement agent placed in thevapor degreaser is 95% (by moles) octane with 5%tridecafluoro-1-iodohexane.

EXAMPLE 6

The solvents that have been in use in a manufacturing facility fordegreasing of metal parts (CFC-113, 1,1,1-trichloroethane, and Stoddardsolvent) are removed and recycled, reclaimed, or destroyed in anenvironmentally acceptable manner. During manufacturing, a metalcomponent is found to be contaminated on the surface with 350 centistokemachining oil and 250,000 centistoke silicone grease. From a squirtbottle in a fume hood the component is rinsed with1,1,2,2,3,3,4,4,4-nonafluoro-1-iodobutane; wiped with a clean cloth, andallowed to air dry. Within 15 minutes it is dry and the surface is cleanand ready for further processing. This cleaning process did not depletestratospheric ozone or pose a flammability or toxicity risk to thetechnician or require excessive investment in engineering controls.

EXAMPLE 7

A gyroscope contaminated with MIL-H-5606 hydraulic fluid is placed in anultrasonic cleaning machine filled with tridecafluoro-1-iodohexane. Acrossdraft local exhaust removes any escaping vapors and the bath issubjected to 2 watts/cm² ultrasonic energy for 5 minutes. The gyroscopeis removed, allowed to drain, and hot-air dried. The resulting veryclean gyroscope is carefully packaged and sent on for furthermanufacturing or installation.

EXAMPLE 8

In a dry cleaning operation the perchloroethylene used is removed andrecycled or destroyed in an environmentally sound manner. These solventsare replaced with a blend of 5% (by moles) CF₃ (CF₂)₅ I and 95%petroleum distillate consisting primarily of heptane and octane. The newsolvent is effective, nonflammable, and much less toxic than thesolvents replaced. Furthermore, it is less damaging to the environmentbecause the risk of ground water contamination by the long-lived speciesperchloroethylene is eliminated.

EXAMPLE 9

An alkyd enamel paint is formulated using (instead of pure mineralspirits) a blend of 95% (by moles) mineral spirits and 5%1-iodoperfluorohexane. The addition of the fluoroiodocarbon renders theformulation nonflammable and safer to use.

EXAMPLE 10

An adhesive is formulated using (instead of 1,1,1-trichloroethane) ablend of 95% (by moles) toluene and 5% 1-iodoperfluorohexane. By thischange the adhesive is made nonflammable and less harmful to theenvironment.

EXAMPLE 11

A polyurethane foam is blown using as the blowing agent a mixture of 5%by moles pentafluoroiodoethane with 95% pentane. In contrast to foamsblown using CFC-11, during the manufacturing process none of the vaporsreleased cause ozone depletion. In addition, because of the addition ofthe fluoroiodoalkane, the foam is rendered nonflammable. Finally, at theend of its useful life, when the foam is disposed of, no damage tostratospheric ozone occurs.

EXAMPLE 12

A can of hair spray is pressurized with a mixture of 4% (by moles) CF₃ Iand 96% butane and/or isobutane. There is no flammability risk; even ifthe spray can is accidentally discharged over an open flame no ignitionoccurs. Discharge of the contents of the can causes no damage tostratospheric ozone.

EXAMPLE 13

A spray can of household disinfectant is pressurized with a mixture of4% CF₃ I and 96% carbon dioxide. Because of the use of thefluoroiodocarbon blend as propellant, any flammability risk iseliminated.

EXAMPLE 14

A gas mixture consisting of 5% (by moles) CF₃ I, 12% ethylene oxide, and83% nitrogen is used to sterilize bandages, gauze pads, and medicalequipment. Because of the addition of the CF₃ I as a supplementalpropellant, the danger of fire or explosion during the process iseliminated.

EXAMPLE 15

The charge of Halon 1301 is removed from a computer room fire protectionsystem and taken for recycling or destruction. In its place, with minormodifications of the system (such as changes in gaskets, O-rings, andnozzles) is placed a gas mixture consisting of 60% (by moles) CF₃ I and40% CF₃ CH₂ F. In the event of a fire, the new agent rapidly dispersesand extinguishes the fire without harming personnel or damagingequipment. No ozone depletion occurs from the emission of thefirefighting agent.

EXAMPLE 16

The Halon 1211 in a 150-lb wheeled flightline extinguisher at an airportis removed and taken for recycling or destruction. In its place, withminor modifications to the extinguisher (such as changes in gaskets,O-rings, and nozzles), is put a mixture of 70% (by moles)1,1,2,2,3,3,3-heptafluoro-1-iodopropane and 30% perflurohexane. In caseof fire the liquid agent is manually directed as a stream at the base ofthe flames and rapidly extinguishes the fire without harming personnelor damaging equipment. No ozone depletion occurs from the emission ofthe firefighting agent.

EXAMPLE 17

A cylinder containing approximately 1 lb of CF₃ I sealed with a leadplug is mounted under the hood of a vehicle. In case of fire, theextinguisher is activated passively as the lead plug melts and theextinguishing agent is automatically discharged, extinguishing the fireand protecting the occupants, vehicle, and contents.

The preceding examples can be repeated with similar success bysubstituting the generically or specifically described reactants and/oroperating conditions of this invention for those used in the precedingexamples.

Although the invention has been described in detail with particularreference to these preferred embodiments, other embodiments can achievethe same results. Variations and modifications of the present inventionwill be obvious to those skilled in the art and it is intended to coverin the appended claims all such modifications and equivalents. Theentire disclosures of all references, applications, patent, andpublications cited above are hereby incorporated by reference.

We claim:
 1. A method of using a solvent to clean a surface of an article, comprising the steps of providing a solvent to an applicator, and applying the solvent from the applicator to a surface of an article to remove a contaminant from the article surface, wherein the solvent comprises a blend of at least one fluoroiodocarbon of the formula C_(n) H_(b) Br_(c) Cl_(d) F_(c) I_(f) N_(g), wherein a is between and including 1 and 8, b is between and including 0 and 2, c, d and g are each between and including 0 and 1, e is between and including 1 and 17, and f is between and including 1 and 2, with at least one additive selected from the group consisting of alcohols, esthers, ethers, fluoroethers, hydrocarbons, hydrofluorocarbons, ketones, and perfluorocarbons, the blend comprising 5 to 75 mol percent of the fluoroiodocarbon and 25 to 95 mol percent of the additive, and being nonflammable and electrically nondconductive, the fluoroiodocarbon having an ozone depletion potential less than 0.02 and a global warming potential less than that of chlorofluorocarbons, and the additive being nonreactive with the fluoroiodocarbon and not adversely affecting said properties of the fluoroiodocarbon, with the provision that when a is 1, the fluoroiodocarbon is selected from the group consisting of fluoroiodomethane, difluoroiodomethane, difluorodiiodomethane, bromodifluoroiodomethane and chlorodifluoroiodomethane.
 2. The method of claim 1, wherein the fluoroiodocarbon is selected from the group consisting of bromodifluoroiodomethane, chlorodifluoroiodomethane, 1,1,2,2,3,3,4,4,5,5-decafluoro-1,5-diiodopentane, difluorodiiodomethane, difluoroiodomethane, 1,1,2,2,3,3,4,4,5,5,6,6-dodecafluoro-1,6-diiodohexane, fluoroiodomethane, 1,1,1,2,3,3,3-heptafluoro-2-iodopropane, 1,1,2,2,3,3,3-heptafluoro-1-iodopropane, 1,1,2,2,3,3-hexafluoro-1,3-diiodopropane, iodoheptadecafluorooctane, iodoheptafluorocyclobutane, 1-iodopentadecafluoroheptane, iodopentafluorocyclopropane, 1-iodotridecafluorohexane, 1-iodoundecafluoropentane, n-iodobis-(trifluoromethyl) amine, 1,1,2,2,3,3,4,4,4-nonafluoro-1-iodobutane, 1,1,2,2,3,3,4,4-octafluoro-1,4-diiodobutane, pentafluoroiodoethane, 1,1,2,2-tetrafluoro-1,2-diiodoethane, 1,1,2,2-tetrafluoro-1-iodoethane, and 1,1,2-trifluoro-1-iodoethane.
 3. The method of claim 1, wherein the additive comprises an alcohol selected from the group consisting of 1-butanol, 2-butanol, ethanol, methanol, 2-methyl-1-propanol, 2-methyl-2-propanol, 1-pentanol, 2-pentanol, 1-propanol, and 2-propanol.
 4. The method of claim 1, wherein the additive comprises an ester selected from the group consisting of ethyl acetate, hexyl acetate, n-pentyl acetate, isopropyl acetate, and methyl acetate.
 5. The method of claim 1, wherein the additive comprises an ether selected from the group consisting of diethyl ether, diisopropyl ether, dimethyl ether, di-n-butyl ether, di-n-propyl ether, 1,4-dioxane, ethylene oxide, propylene oxide, and tetrahydrofuran.
 6. The method of claim 1, wherein the additive comprises a fluoroether selected from the group consisting of bis-difluoromethyl ether, hexafluorodimethyl ether, hexafluorooxetane, methyl trifluoromethyl ether, octafluorodimethoxymethane, octafluoro-1,3-dioxolane, pentafluorodimethyl ether, 1,1,2',2',2'-pentafluoro methyl ethyl ether, and 1-trifluoromethoxy-1,1,2,2-tetrafluoroethane.
 7. The method of claim 1, wherein the additive comprises a hydrocarbon selected from the group consisting of decane, 2,3-dimethylpentane, 2,4-dimethylpentane, 2,2-dimethylpropane, heptane, hexane, isobutane, ligroin, 2-methylbutane, 3-methylexane, 3-methylpentane, mineral spirits, naphtha, nonane, octane, pentane, petroleum ether, petroleum spirits, pinene, propane, Stoddard's solvent, turpentine, and undecane.
 8. The method of claim 1, wherein the additive comprises a hydrofluorocarbon selected from the group consisting of difluoromethane, 1,1-difluoroethane, 1,1,1,2,3,3,3,-heptafluoropropane, pentafluoroethane, 1,1,2,2,3-pentafluoropropane, 1,1,1,2-tetrafluoroethane, 1,1,1-trifluoroethane, and trifluoromethane.
 9. The method of claim 1, wherein the additive comprises a ketone selected from the group consisting of acetone, 2-butanone, and 3-methyl-2-butanone.
 10. The method of claim 1, wherein the additive comprises a perfluorocarbon selected from the group consisting of decafluorobutane, dodecafluoropentane, hexafluorocyclopropane, hexafluoroethane, octafluorocyclobutane, octafluoropropane, tetradecafluorohexane, and tetrafluoromethane.
 11. The method of claim 1, wherein the fluoroiodocarbon comprises CF₃ CF₂ CF₂ I and the additive comprises diethyl ether.
 12. The method of claim 1, wherein the fluoroiodocarbon comprises CF₃ CF₂ CF₂ I and the additive comprises pentane.
 13. The method of claim 1, wherein the fluoroiodocarbon comprises CF₃ (CF₂)₃ I and the additive comprises acetone.
 14. The method of claim 1, wherein the fluoroiodocarbon comprises CF₃ (CF₂)₃ I and the additive comprises methyl acetate.
 15. The method of claim 1, wherein the fluoroiodocarbon comprises CF₃ (CF₂)₃ I and the additive comprises methanol.
 16. The method of claim 1, wherein the fluoroiodocarbon comprises CF₃ (CF₂)₃ I and the additive comprises tetrahydrofuran.
 17. The method of claim 1, wherein the fluoroiodocarbon comprises CF₃ (CF₂)₃ I and the additive comprises hexane.
 18. The method of claim 1, wherein the fluoroiodocarbon comprises CF₃ (CF₂)₄ I and the additive comprises ligroin.
 19. The method of claim 1, wherein the fluoroiodocarbon comprises CF₃ (CF₂)₄ I and the additive comprises ethanol.
 20. The method of claim 1, wherein the fluoroiodocarbon comprises CF₃ (CF₂)₄ I and the additive comprises butanone.
 21. The method of claim 1, wherein the fluoroiodocarbon comprises CF₃ (CF₂)₄ I and the additive comprises 2-propanol.
 22. The method of claim 1, wherein the fluoroiodocarbon comprises CF₃ (CF₂)₄ I and the additive comprises ethyl acetate.
 23. The method of claim 1, wherein the fluoroiodocarbon comprises CF₃ (CF₂)₄ I and the additive comprises isopropyl acetate.
 24. The method of claim 1, wherein the fluoroiodocarbon comprises CF₃ (CF₂)₄ I and the additive comprises heptane.
 25. The method of claim 1, wherein the fluoroiodocarbon comprises CF₃ (CF₂)₅ I and the additive comprises heptane.
 26. The method of claim 1, wherein the fluoroiodocarbon comprises CF₃ (CF₂)₅ I and the additive comprises toluene.
 27. The method of claim 1, wherein the fluoroiodocarbon comprises CF₃ (CF₂)₇ I and the additive comprises limonene.
 28. The method of claim 1, wherein the fluoroiodocarbon comprises CF₃ (CF₂)₇ I and the additive comprises hexyl acetate.
 29. The method of claim 1, wherein the fluoroiodocarbon is CF₃ (CF₂)₂ I, CF₃ (CF₂)₃ I, CF₃ (CF₂)₄ I or CF₃ (CF₂)₅ I.
 30. The method of claim 1, wherein the contaminant is a hydrophobic soil.
 31. The method of claim 1, wherein ultrasonic energy is applied to the surface of the article having the solvent thereon.
 32. A method of using a solvent to clean a surface of an article, comprising the steps of providing a solvent to an applicator, and applying the solvent from the applicator to a surface of an article to remove a contaminant from the article surface, wherein the solvent comprises a blend of at least one fluoroiodocarbon of the formula C_(n) H_(b) Br_(c) Cl_(d) F_(e) I_(f) N_(g), wherein a is between and including 1 and 8, b is between and including 0 and 2, c, d and g are each between and including 0 and 1, e is between and including 1 and 17, and f is between and including 1 and 2, with at least one additive selected from the group consisting of esters, ethers selected from the group consisting of diethyl ether, diisopropyl ether, dimethyl ether, di-n-butyl ether, di-n-propyl ether, 1,4-dioxane, ethylene oxide, propylene oxide, and tetrahydrofuran, fluoroethers, hydrocarbons, hydrofluorocarbons, ketones, and perfluorocarbons, the blend comprising 5 to 75 mol percent of the fluoroiodocarbon and 25 to 95 mol percent of the additive, and being nonflammable and electrically nondconductive, the fluoroiodocarbon having an ozone depletion potential less than 0.02 and a global warming potential less than that of chlorofluorocarbons, and the additive being nonreactive with the fluoroiodocarbon and not adversely affecting said properties of the fluoroiodocarbon. 